Ty Element Retrotransposition in Saccharomyces cerevisia

酿酒酵母中的 Ty 元件逆转录转座

• 批准号: 7338477
• 负责人: David J. Garfinkel
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7338477
• 关键词: Ty; Element; Retrotransposition; Saccharomyces; cerevisia

Over the past year, we have made progress in the following areas. Ty1 copy number dynamics has been studied by reintroducing active elements into a Ty-less strain where resident elements had been lost by long terminal repeat (LTR-LTR) recombination. Repopulated strains exhibit alterations in chromosome size that are associated with Ty1 insertions, but do not become genetically isolated. The rates of element gain and loss under genetic and environmental conditions known to affect Ty1 retrotransposition have been determined using genetically tagged reference elements. Ty1 gain and loss ratios obtained under different conditions suggest that copy number oscillates over time by altering the rate of retrotransposition, resulting in the diverse copy numbers observed in Saccharomyces. On a broader scale, our results suggest that the gain and loss of LTR-retrotransposons can be highly dynamic and has the potential to remodel genomes over short evolutionary time periods. In collaboration with Dr. Dwight V. Nissley (SAIC, Frederick MD), we have shown that hybrid elements composed of Ty1 and the reverse transcriptase gene from HIV-1 are useful tools for detecting, monitoring, and isolating drug-resistant reverse transcriptases in budding yeast. This sensitive phenotypic assay detects drug-resistant variants in clinical samples when the variants comprise as little as 0.3 to 1.0% of the virus population. Furthermore, our assay can detect of both known and novel reverse transcriptase variants and should be useful in studies of the evolution and clinical significance of minor drug-resistant variants.

在过去的一年中，我们在以下领域取得了进展。通过将活性元件重新引入无链菌株，已经研究了TY1拷贝数动力学，在该元素中，长期重复（LTR-LTR）重组丢失了居民元素。重新填充的菌株在染色体大小中显示出与TY1插入相关的染色体大小的改变，但不会在遗传上分离。在遗传和环境条件下，已知会影响TY1逆转录置位的元素增益和损失的速率已使用遗传标记的参考元件确定。在不同条件下获得的TY1增益和损耗率表明，拷贝数通过改变逆转录的速率随时间推移而振荡，从而导致糖疗中观察到的不同拷贝数。在更广泛的范围内，我们的结果表明，LTR-返回转座子的增益和损失可能是高度动态的，并且有可能在短进化时期重塑基因组。与Dwight V. Nissley博士（SAIC，Frederick MD）合作，我们表明，由TY1和HIV-1的逆转录酶基因组成的混合元素是检测，监测和隔离酵母中抗药性反向转录酶的有用工具。当这种变体占病毒群的0.3至1.0％时，这种敏感的表型测定可检测到临床样品中的抗药性变体。此外，我们的测定可以检测已知和新型逆转录酶变体，并且在研究次要耐药变体的进化和临床意义的研究中应很有用。